Hemolysis of Streptococci- Types and Examples with Images


Streptococcus is a genus of gram-positive bacteria that are spherical or ovoid in shape and grow in pairs or chains. They are non-motile, non-spore forming, and mostly facultatively anaerobic. Streptococci are a diverse group of bacteria that can colonize different sites of the human body and cause various diseases ranging from mild infections to severe or chronic conditions.

One of the main characteristics that has been used to classify streptococci is their ability to lyse red blood cells (RBCs) on blood agar plates. This phenomenon is called hemolysis and it is caused by enzymes (hemolysins) released by the bacteria. Hemolysis can be observed as a zone of clearing or discoloration around the bacterial colonies on blood agar.

There are three types of hemolysis: alpha, beta, and gamma.